Telephone signaling system.



H. L. QUASS.

TELEPHONE SIGNALING SYSTEM.

APPLICATION FILED IULY l, 1916- l ,266,623 Patented May 21,1918.

2 SHEETS-SHEET I.

`/m/en for: 'l V i' Hai/ph L, 006756.

R. L. QUASS.

TELEPHONE SIGNALING SYSTEM` APPLICATION FILED IuLY 1.1916.

Raf/ph L. Quass. by

.RALPH L. QUASS, OF NEW YOR'K, N. Y., ASSIGNOR TO WESTERN ELECTRIC COMPANY,

INCORPORATED, 0F NEW YORK, N. Y., A CORPORAT'ION 0F NEW YORK.

TELEPHONE SIGNALING SYSTEM.

Specification of Letters Patent. Patented May 2li, 191g.

Application filed. July 1, 1916. Serial No. 107,012.

To all whom it may concern.'

Be it known that I, RALPH L. QUAss, a citizen of the United States, residing at New York, in the county of Bronx and State of New York, have invented certain new and useful lmprovements in Telephone. Signaling Systems, of which the following 1s .a full, clear, concise, and exact description:

This invention relates to a telephone signaling system, and particularly to a system of the type in which automatic switches are employed for controlling the connecting and signaling circuits. The invention has particularly to do with an improved organization for effecting the reapplication of signaling current to a called line, -either to recall the subscriber or attendant at the` called station, or to signal some other station on the same line.

In the improved organization hereln disclosed, the arrangement is such that the resignaling of a called line may be eliected without disestablishing the connection that exists between the line and the connecting circuit. rlhis avoids the bringing in o f a false call, which would follow the breaking of connection between the connecting circuit and a called line having a conducting bridge across the line conductors at the called station. Such a bridge is commonly provided at the stations of private branch exchange, or PB X., lines. The improved organization of this invention is also of such a character that, where the various operating stages of the connecting circuit are established and disestablished in a fixed and predetermined cycle by means of a sequence switch, this cycle switch may be moved to set up the particular circuit condition that has to do with the re-signaling of the called line, without altering or establishing other circuit conditions that are not concerned with creating the re-signaling condition of the circuit.

The invention will be explained by reference to the accompanying drawings, in which Figure 1 and Fig. 2 taken together, and with Fig. 1 at the left of Fig. 2, show one of the forms in which the invention may be practised.

The organization illustrated in the drawings, comprises as much of a complete telephone system as is necessary for a clear understanding of the manner in which the ininclusive, and 801 to 316, inclusive.

vention is organized and operates. There are shown in the drawings a calling telephone line extending from a station A to a.

to disconnect the line relay when connection is made with the line.

It is thought that the manner in which the system of the invention is organized will be presented most clearly by proceeding directly to a description or its operation. It will be assumed that the subscriber at station A initiates a call by lifting his tele.- phone receiver from its hook. The hook, in rising, conductively units the two limbs of the line, thus permitting current to flow through and energize the associated line relay 127. As a result, the brushes of the switch 128 are brought into engagement with the terminals of the calling line. The switch 128 may be of the type illustrated and described in Patent No. 1,177,044 to J. L. McQuariie, issued March 28, 1916; but as the particular character of the switching mechanism for extending the connection of the'calling line, and the particular manner in which it is made effective, are not involved in the present invention, they will not be described.

The circuits that are involved in the setting up of a connection between the calling line and a called line by means of the connecting circuit, may be controlled by sequence switches of the type disclosed in Patent 1,127,808 to Reynolds and Baldwin, issued Feb. 9, 1915. These'switches are indicated diagrammatically at 100, 200 and 300 on the drawings, and the switch cams or contacts operated by these three sequence switches, respectively, are indicated by the numerals 101 to 104, inclusive, 201 to e numerals applied to the contacts 101, 201 and 301 indicate the only positions of the switch'in which the associated contacts are :seA

-quence switch contacts indicate the only positions of the corresponding switch in which the associated contacts are closed.

After the conductors of the calling line have been extended to the conductors 117, 119 and 123 by the closure of the contacts of switch 128, these last mentioned conductors are extended to conductors 217 219 and 223 by the closure of the contacts of the switch 129. This switch may be ot' the same character as switch 128, or of any other usual and well-known type.

After the contacts of switch 129 are closed, the sequence switch 100 is moved to posltion 14. In this position, a circuit is closed that extends .through the winding of relays 220 and 221 in parallel, sequence switch contacts 305 (1), sequence switch contacts 205 (1), left-hand resting contact and amature of relay 222, conductor 223, contacts of swltch 129, sequence switch contacts 104 (9i-14 and 12 to 14), relay 126, conductor 123,. contacts of switch 128, to ground by way of cut-oii' relay 125 of the calling line. Relay 220, -1n operating, closes, in the front contact of its armature 224, a circuit for advanclng the operators listening key sequence switch 200 out of its l position, this clrcuit extending from battery by Wayof the motor magnet and cam 202 (1) of the sequence switch, cam 306 (17 to 8 and 1) of calling cord sequence switch 300, and front contact 2 24 of relay 220 to ground. At the same instant, relay 221 in operating closes an energizing circuit for relay 222, this circuit extending rom grounded battery through the winding of relay 222 and to ground by way of contacts 225 of relay 221. Relay 220 also closes a locking circuit for itself and relay 221 by way of its front contacts 226, cam 307 (l) of calling,cord sequence switch 300, and cam 206 (1 to 6) of the listening key sequence switch, to ground.

When the energizing circuit of the motor magnet of listening key sequence switch 200 is closed by the operation of relay 220, as previously described, sequence switch 200 moves out of its 1 or normal position, and into its 7 or listening-in position. As soon as it leaves its 1 position, the sequence switch 200 closes in its contacts 207 (2 to 7) a circuit that maintains the energization of relay 222. Relay 222, in operating, disconnects the sleeve conductor 223 Jfrom the windings of relays 220 and 221, and connects it to batt-ery through the winding of relay 227. Relay 227, inl operating, closes a normal break in the ring conductor of the connecting circuit.

The current that now flows by way of the winding of relay 227 and the front contacts of relay 222 to conductor 223, passes through the winding of the relay 126V; and this relay acts as long as it is energized to maintain the connection between the calling line and the connecting circuit, and to release the connection when it is denergized. The continuance of the connection is therefore also dependent upon the maintained energization of the relay 222.

As traced in the foregoing, the extending of the calling line to the connecting circuit has energized the relays 220 and 221, and they, in turn, have'caused the operation of the relay 222 and have moved thev listening key sequence switch 200 out of its normal `and into its 7 or listening-in position. In

this position, the listening key' sequence switch brings the operators telephone set 230 into connection with the connecting circuit through the medium of sequence switch cams 203, 204, 208 and 209 closed in the 6 to 8 position of the switch. That is, these cams act in the listening-in position of the sequence switch to interrupt the connecting circult, and connect itssevered ends with a loop that -extends to the operators telephone set and apparatus by means of which the operator controls the connection.

By means of her telephone apparatus, the operator communicates with the calling subscriber and learns the number of the line with which he desires connection. She then tests the line by touching the tip of the calling plug 325 to the sleeve of the called line jack. If the line is busy, the usual test potential on the sleeve of the line jack is communicated by way of the tip of the plug and resting contacts of the relay 330 to operate the test relay 231 associated with the operators telephone set. This relay, in operating, causes an impulse of current to flow through the test winding 232 of the operators induction coil. If the line is not busy, no test impulse flows, and the operator inserts the plug in the jack.

The insertion of the plug closes an energizing circuit for relays 330 and 331 by way of the sleeve conductor and the cut-oi relay of the called line. Relay 330, vin operating, disconnects the tip of the calling plug 325 from the operators busy test apparatus and connects it with the tip conductor of the talking circuit. Relay 330, in operating, also closes an energizing circuit that causes the calling cord sequence switch 300 to move outI of its normal or 1 position. This circuit maybe traced from battery through the motor magnet and cam 303 (1) of the calling cord sequence switch, cam 210 (7) of the listening key sequence switch, the righthand front contact and armature of relay 330to ground. When the calling lcord sequence switch reaches its 2 position, it closes a circuit that moves the listening key sequence switch out of its 7 or listening-in position, this circuit extending from battery through the motor magnet and cam 211 (7) and upper contact of the listening key sequence switch, calling cord sequence switch contacts 30S (2), and the back contact and armature 224 of relay 220 to ground. In

` moving through its 8 position on the way to its 15 position, which' is the next resting position, the listening key sequence switch 200 closes an energizing circuit for the calling cord sequence switch 300, which moves that switch out of its 2 position. This circuit' extends from battery through the motor magnet and cam 304 (2) of the calling cord sequence switch, listening key sequence switch contacts 210 (8 to 15), and righthand front contact and armature of relay 330 to ground.

When a calling cord sequence switch reaches position 4, a circuit is closed that extends from battery through the motor mag net and cam 304 (4 to 13) of the calling cord sequence switch, and the right-hand back contact and armature of relay 332 tol ground, which circuit continues the movement of the switch beyond position 4. In the embodiment of the invention illustrated the calling cord sequence switch is stopped in position 13 to apply ringing current to the called subscribers line. This is effected in the following manner: As the calling cord sequence switch passes through position 12, it closes a circuit that causes the operation of the relay 332. This circuit extends from battery through the winding of relay 332, normal contacts of relays 333 and 334, c alling cord sequence switch contacts 306 (12 to 13 and 10 to 15), and calling cord sequence switch contacts 309 (3 to 13) to ground. Relay 332', in operating, opens in its resting contacts the energizing circuit for the motor magnet of calling cord sequence switch 300 that extends by way of cam 304 (4A to 13) of the calling cord sequence switch. This causes the calling cord sequence switch to stop in the neXt resting position, which is position 13. Relay 332, in its left-hand front contacts, also closes a normal break in the path by means of which ringing current is to he applied.

When the calling cord sequence switch comes to rest in its 13 position, it closes the following circuit for ringing the called subscribers station: From the ringing generator 335, by way of the commutator 336, which eHects the alternate application of current from the ringing generator and from the battery, through the calling cord sequence switch contacts 311 (13), winding of relay 334, left-hand front contacts of relay 332, sequence switch contacts 312 (13), ring contacts of the calling plug and called line spring jack, and one side of the called line to ground, by way of the condenser and bell at the called subscribers station, the other side of the called subscribers line, tip contacts of the plug and jack, armature and front contact of relay 330, and calling cord sequence switch contacts 313 (13) to ground,

assuming that the plug 325 is in the ack 413 of the line 'extending to station C.

It may be seen from the foregoing that the movements of the calling cord sequence switch to apply ringing current to the called subscribers line is controlled by the listening key sequence switch, the movement of the calling cord sequence switch out of normal being possible only when the listening key sequence switch is in the listening-in position, and the subsequent movement of the switch to apply ringing currents being effected by the movement of the listening key sequence switch out of the'listening-in position.

When the called subscriber responds to the call by taking his telephone from its hook, the relay 334 is energized. This relay may be provided with a copper sheath so as to make it relatively insensitive to the relatively small flow of the alternating current that rings the called subscribers bell, but which leaves it fully responsive to the current that fiows over the line circuit and to ground by way of the calling cord sequence switch contacts 313 (13) when the called subscriber lifts his telephone receiver.

The relay 33.4 in attracting its armature upon the response of the called subscriber, opens a short circuit that normally exists about the winding of the relay 333. The last mentioned relay in operating closes a path from battery by way of resistance coil 337 that shunts out relay 332 and causes that relay to release its armatures. Relay 333, in operating, also opens in its own left-hand resting contacts the short circuit about its own winding, iirst opened by the response of the relay 334. The release of relay 332 opens in its left-hand front contacts the path over which ringing current is being applied, and also closes in its right-hand back contact an energizing circuit that moves the calling cord sequence switch out of its 13 or ringing position. This path extends from battery through the motor magnet and cam 304 (4 to 13)V of the calling cord sequence switch to ground by way of the right-hand back contact and armature of relay 332 that has just been released.

The calling cord sequence switch thereupon moves out of its 13 and into its 16 or next resting position. In moving out of position 13, the sequence switch disconnects from the tip and ring conductors of the calling cord the circuit over whichl the ringing operation has taken place, and in the 16 and 17 positions of the switch connects these conductors through, by way of the 312 cam and 313 cam, to complete the talking circuit. In moving out of position 13, it also causes the denergization of relay 333 by breaking its circuit in sequencev switch contacts 3 06 (12 to 13).

In position 16 of thecalling cord sequence ers line; and as the called subscriber has his telephone oil' the hook, the relay is energized and closes a circuit for movingl the calllng/ cord sequence switch out of position 16. This circuit isv by way of cam 303 (16) and the front contacts of supervisory relay 338. The sequence switch 300 then moves into position 17.

As long as the subscribers are at their telephones, the supervisory lamps 339 and 340 are shunted out in contacts of the corresponding supervisory 'relays 342 and 338. When the telephones are replaced on their hooks, the supervisory relays become inert and open the shunts, and the lamps light, thus giving the operator the disconnect signal.

But, in the present instance, it will be assumed that after the called subscriber'has hung up and before the voperator has taken down the connection, the calling subscriber wishes again to get into communication with the called subscriber. He may manifest this to the operator either by moving his telephone hook up and down, whichlcauses the answering supervisory lamp 339 to flash, or

merely by remaining athis telephone, in.

which case his associated lamp 339 remains dark and thus fails to 'complete thefdisconnect indication which involves the lighting of both lamps. In either case the o erator i knows that the connection requires urther attention, and therefore brings her telephone set into connection with the cord circuit. She does this by depressing the listening-in key 233.

Previous to this the listening key sequence switch 2 00 has been standing in its listening-out or 15 position'. When the operator presses the listening-in key 233, a circuit is closed that moves the listening key sequence switch out vof this position, this circuit extending from battery throu h the motorl magnet andcam 202 (15) of t e lisc tening key sequence switch, and to ground by way of the key 233. When the sequence switch 200 reaches its normal or 1 position, it doesnot stop there, but moves on as a result of the circuit that is closed for its motor magnet by way of its associated contacts 202 (1) and contacts 314 (2 to 18) of the calling cordsequence switch to ground. The result, therefore, of pressingthe key 233 while the calling plug is still in the called line spring jack is to move the listening key sequence switch from its listening-out position 15 to its listening-in position 7.

In position 7 of the listening key sequence switch,` the cams 203, 204, 208 and 20,9 operate to connect into the talking circuit the loop which extends to the operators telephone set, and the operator is thus enabled to communicate with the calling subscriber.

Learning that the calling vsubscriber desires to have the called. subscriber 'called to his telephone again, the operator momentarily y,depresses the re-ring key 234. This closes a circuit that extends from battery through the windings of relays 220 and 221 in multiple, and thence by way of contacts 305 (4 to 17) f the calling cord sequence switch, contact 212 (7) of the listening key sequence switch, lower contact of the re-ring key 234, winding of relay 228, and listening key sesequence switch contact 206 (7) to' ground. The relay 228 is of suliiciently high resistance to prevent the operation of relays 220 and 221. But it is itself energized, and in attracting its armatures, closes a vlocking circuitk for itself by way of the normal contacts of relay 229 and resistance 235 to battery. It also applies ground directly to the` upper contact of the re-ring key 234, so

, that when that key is released after a moto ground through the high resistance winding of relay 228, and are thus energized. The object of the above described arrangement is to prevent the possibility of a recurrent operation of the relays 220 and 221 by an unduly lon depression of the re-ring key 234. The loc 'ng circuit of relay 228 is broken when, in the subsequent operation,

the relay 229 is actuated by the closure of v its energizing circuit in calling cord sequence switch contacts 310 (12 to 34.)

The effect of pressing the re-ring key is to bring about certain circuit changes that cause ringing current to be reapplied to the called subscribers line without otherwise connection. When the relay 221 operates, it

closes' an energizing circuit for the motor magnet of the calling cord sequence switch 300 to move the switch out of position 17, this circuit extending from battery through the motor magnet and. cam 302 (2 and 4 .to 17) of the calling cord sequence switch, and right-hand vfront contact and armature of relay 221 to ground.

In the ordinary disconnect operation, when the calling cord sequence switch moves out of its 1'? or talking position, it breaks, in its cam 310, the locking circuit for the holding relay 222, this relay thereupon becoming inert and releasing the connection by breaking the circuit of the sleeve conductor 223. But in the rering operation, the operator is in on the connection, and the holding relay 222 therefore has a circuit to ground by way of the contacts 207 (2 to 7) of the listening key sequence switch, that holds it energized when its locking circuit is broken in cam 310 (E to 171) of the calling cord the connection,

Lacasse holding circuit of relay 222 is brokenat cam 207 but is maintained through contacts 225 ofv relay 221. Relay 221 is maintained energized over a locking circuit through connecting cord sequence witch contact 307 (4 to 2i) tofgroundvat the right-hand armature and front contact of relay 330. The holding up of `relay 222 preventsthc'denergization of relay 126 which would result in the movement ofthe calling cord circuit switch.

In the ordinary disconnecting operation,4

the calling cord sequence switch, after it is moved out of position 17, comes to-rest in its normal or 1 position. But-in therering operation,- as the operator is in on the connection and the calling lug is inserted in the called line jack, a circuit is completed in the 1 position that causes the calling cord sequence `switch to continue moving. This circuit extends from batter motor magnet and cam 303 1) of the calling cord sequence switch, cam 210 (7) of the listening key sequence switch, and righthand front contact and armature of relay 330 to ground. l

In the ordinary connecting operation, when the calling cord sequence switch moves into its 2 position, it closes a circuit that moves the listening key sequence switch out of its 7 or listening-in position and into its 15 or listening-out position, this circuit extending from battery through the motor magnet and cam 211 (7) of the listening key sequence switch, and to ground by way of cam 308 (2) of the calling cord sequence switch and resting contacts 224 of the relay 220. But, in the rerin operation, the relays 220 and 221 are both initially energized by the depression and release of the rering key 234, and are thereafter locked up by way of a holding circuit through the contacts 226 of relay 220, calling cord sequence switch cam 307 (4 to 2i), and right-hand front contact and armature of relay 330 to ground. Therefore, the previously traced circuit by way of the resting contacts 224 of relay 220 is open, and the movement of the calllng cord sequence switch 300 into position 2 does not listening key sequence switch out move the of its listening position 7.

In the ordinary connecting operation, the calling cord sequence switch, as previously described, is moved out of the 2 position by a circuit that is completed in cam 210 (8 to 15) of the listening key sequence vswitch when that switch moves out of its listeningin position. In the rering operation, as the listening key sequence switch stays 1n its 7 position to enable the operator to supervise the calling cord sequence switch is moved through its 2 .position by the circuit, by way of calling cord sequence switch cam 302 (2 and 4 to 17) and front contacts. of relay 221, that moved it out of '05 talking position when the rering key 234 "ing through the a was pressed. In 'moving out of its 2 position, the calling cord sequence switch opens in its cam 307 (4 to 24) the holding circuit.

for the relays 220 and 221, which relays thereupon release.

From this point on, the o eration is as heretofore described, the ca ingcord uence switch moving to its ringing position 13 and there awaiting the response of the called subscriber to restablish the talkcondition ofv the circuit. But, in this case, the listening key se uence switch 200 remains in its 7 or llstenlng-in position to enable the operator to supervise the connection and may be moved out of this position by depressing the master listening-out vkey 236.

When the operator is apprised of the completion of the conversation by the lighting of both supervisory lamps 339 and 340, .she removes the calling plug 325 from the called line jack. The resultant denergization of relay 330 closes an energizing circuit for relay 237, this circuit extending 'from battery through the windin of relay 237, cam 315 (2 to 17 of the ca lin cord sequence switch, and right-hand bac contact and armature of relay 330 to ground. Relay 237, in operating, closes a holding circuit for itself by way of cam 315, its own right-hand front contact and armature and cam 316 (2 to 17 to ground. Relay 237 also closes a circuit that moves the calling Acord sequence switch out of its talking position 17. This circuit extends from battery through the motor magnet and cam 303 (2 to 17 of the calling cord sequence switch, left-hand front contact and armature of relay 237, and cam 314 (2 to 18) of the callcord sequence switch to ground.

In moving out of its talking position 17 the calling cord sequence 'switch opens, in its contacts 310 (l to 179g), the holdin circuit for the relay 222, which relay, invfaglling back, opens the circuit of thesleeveconductor 223. Relay 126, being included in this circuit, thereupon releases, and closes in its back contact a circuit by way of cam 102 (14) for moving the corresponding sequence switch 100 out of its talking posltion 14. Sequence switch 100 then moves from one to another of its positions, under the control of parts that it is not necessary to show or describe, until it reaches its normal or 1 position. In this movement of sequence switch 100, the switch 128 may be returned to normal when the circuit of its down-drive ma et 12'1 is completed in sequence switch contacts v103 (16.), and the switch 129 may be returned when the circuit of its downdrive magnet 122 is completed in sequence switch contacts 105 (17 When the calling cord sequence switch reaches its normaljor 1 position, it closes a circuit that moves the listening key sequence switch from its 15 position back to normal, this circuit extending from battery through the motor magnet and cam 211 (15) of the listening vkey sequence switch to ground by way of calling cord sequence switch cam 308 (1) and the resting contacts 224 of relay 220.

, When the connecting cord circuit is used with ordinary subscribers lines, such as the called line C,'it is possible for the operator to bring about a reapplication of ringing current to the vcalled subscribers line by withdrawing the calling plug from the called subscribers jack and then reinserting it. In this case, the operator, when she notes by the indication of the supervisory lamp signals that the calling subscriber requires further attention, brings her telephone into connection with the circuit by pressing her listening-in key, the listening key sequence switch being thereby moved into its 7 position in the manner already described. Upon learning that the called sub scriber isl to be resignaled, she may, if the called line is not a private branch exchange line, effect the reapplic'ation of ringing current by withdrawing the calling plug and reinserting it. The withdrawal of the plug acts, by releasing the relay 330 and thereby energizing the relay 237, to move the calling cord sequence switch out of its 17 position. But as the listening key sequence switch is in its 7 position and thereby holding the relay 222 energized, the movement of the calling cord sequence switch does. not disconnect the calling subscriber from the connecting cord circuit. The withdrawal of the calling plug, therefore, acts merely to return the calling cord sequence switch to normal without releasing the connection with the calling line. When the operator reinserts the calling plug, the calling cord sequence switch is advanced to its 13 or ringing position in the same way that it was described as being advanced when the connection was irst put up. The listening key sequence switch is also moved from its 7 to its 15 position, so that in the act of reringing in this way the operator is auto# matically disconnected.

While reringing may be accomplished as above described by withdrawing and reinserting the plug where the called line is an ordinary subscribers line, this method is, in certain respects, inconvenient and unsatisfactory, and if the line is a party line, other stations than the one desired may be signaled; and where the called line is a private branch exchange line, it gives rise to certain accidental and objectionable operations. The reason is that it is customary to employ, at' private branch exchanges, circuits that place a conducting bridge across the private branch line as soon as the private branch operator answers a call, which bridge, if the main exchange operator were v to withdraw the plug fromthe jack before the private branch exchange operator took down the connection, would originate a false call.

Thus, referring to the rivate branch exchange line diagrammatically indicated as c convenient manner while the circuit at station B is in use. As long as this bridge is closed, the withdrawal of calling plug 325 from spring jack 412, would cause corresponding cut-olf relay 125 to release, line relay 127 to energize, and a signal to be displayed or a finder switch started, the same in effect as though the called station B were calling. The system of the invention, in providing for resignaling without withdrawing the calling plug from the jack, prevents such action from occurring. When the re-ringing key 234 is operated and the calling cord sequence switch moves out of its talking position, as already described, the temporary opening of thetalking conductors permits relay 410 to release. The contacts 414 are closed at this time, and a circuit for energizing relay 415 is completed by Way of one winding of that relay and the back contacts' of relay 410. Relay 415, in operating, closes aKcircuit that includes the other of its windings and a re-call lamp 416, the contacts 417 at the time being closed. In response to the lighting of this lamp, the operator at the private branch exchange station may bring her telephone into connection with the circuit and then perform the resignaling operation that is required; after which, by causing'the opening of the contacts 417, she may 'releasethe relay 415 and extinguish the lamp 416.

The' signaling of the private branch exchange station, when the station is first called, may be effected through the medium of the relay 418 and the lamp 419. The ringing current applied to the line passes through the condenser 420, -and energizes the relay 418, the contact 421 at this time being closed. The relay 418 thereupon locks up, lighting the calling lamp 419. In. responding to the call, the operator may open the contacts. 421, thus releasing the relay and extinguishing the lampt What is claimed is:

1. In a telephone system, the combination with a calling line and a called line and a connecting circuit uniting the same, of a source of ringing current, a cyclic switch adapted in one' of its operative stages to apply ringing current to said connecting circuit to ring said called line, and adapted at a later stage to disestablish the connection of said connecting circuit with said iio . calling line, means for causing said switch cuit, other circuits established in other op` erative sta es of said switch, means for movingsai switch out of its talking stage through said other stages and back into its talking stage again, means for preventing said switch from establishing certain of said other circuits as it passes through the cor-` responding stages, and a signal device associated with said telephone line and made operative by the cyclic switch as said switch moves through said intermediate stages.

3. The combination with a telephone line and a connecting circuit therefor of a signal device associate lwith said telep one line, a cyclic switch for 'said connecting circuit adapted in its operation to establish a condition that causes the operation of said signal device, other circuits adapted to be set l up by said cyclic switch in other stages of its operation, a switch for moving said cyclic switch through its various other stages to reestablish its signal operating stage, and means made active in actuating said last mentioned switch for preventing said cyclic switch from setting up certain of the aforesaid circuit conditions in passing through the corresponding stages.

4. The combination with a connecting cord circuit, of a source of ringing current,

a sequence switch Jfor controlling the connection of said source of ringing current with said cord circuit, connection terminals for said cord circuit adapted when closed to complete a circuit to move said sequence switch into position to apply ringing current `to the circuit, means for moving said sequence switch to cut oli' the ringing current, and are-ring key for moving said sequence switch to reapply ringing current.

5. The combination with a telephone line, of a spring jack therefor, a plug-terminated connecting circuit, a source of ringing current, a sequence switch for controlling the` application` of ringing current from said source to said circuit, means made operative` by the insertion of the plug into the spring jack for moving said sequence switch into itsringing position, means .for moving the sequence switch to lcut oii" the ringing current and' establish the talking condition of the circuit, and a key adapted to move said sequence switch to edect a reapplication of ringing1 current to the circuit.

6. T e combination with a connecting circuit, of a source of ringing current, a sequence switch for controlling' the applicaltion.. of ringing current to said circuit, connection terminals for said connecting circuit adapted when closed to move said sequence switch into its ringing position, operators. telephone equipment, 'a switch for connectingsaid telephone e uipment with said. circuit, means operate by said sequence switch in moving into its ringing position for disconnecting said telephone equipment from the circuit, and an operators key adapted to render said disconnecting means inoperative.

The combination with a telephone connecting circuit, of a source of 'ringing vcurrent, 'a sequence switch for controlling the connection of said source with said circuit, connectionterminals for said connecting circuit adapted when operated to move said operators telephone equipment, means for connecting said 1 telephone e uipment withr said circuit, means operate by said sequence switch in moving into its ringing position for disconnecting said telephone equipment from the circuit, means for moving said sequence' switch out of its ringing position, and a key adapted whenoperative to move said sequence switch again into its ringing position and at the same time render inoperative said telephone equipment disconnecting means.

8. In a telephone system, the combination with a calling and a called subscribers line,

sequence switchl ntoits ringing position,

of aconnecting circuit for uniting the same for conversation, a sequence switch adapted to control the circuit changes of said connecting circuit, a source of ringing current adapted to be applied to the connecting circuit to ring the called subscriber in one of the positions of said sequence switch, means actuated by the response of the called subscriber for moving said sequence switch out of its ringing and into its talking position, means for causing said sequence switch to move out of its talking position and return to normal, a switch automatically operated to disconnect said calling line when the sequence switch moves out of its talking position, and a key adapted when operated to cause said sequence switch to move out of its talking position through its normal position and into its ringing position and adaptconnection of said source of ringing current with saidcord circuit, connection terminals for said cord circuit adapted when closed to cause the movement of said electromagnetic switch into position to apply lringing current to the circuit, means for movmg said switch to cut 0E the ringing current, a controlling circuit for said switch for moving the same to reapply ringing current, and a key adapted when depressed to prepare said controlling circuit for closure and when released to close the same.

10. The combination with a connecting circuit, of two telephone lines connected thereby, an automatic switch controlhng the connection of one of said lines `with said circuit, an electromagnetic switch cpntrolling the continuity of said connecting circuit, means made operative in the breaking of the continuity of said circuit by said last mentioned switch to operate said automatic switch to break connection between the connecting circuit and the corresponding` line, and means for operating said electromagnetic swi'tch and at the same time preventing the operation of said .lau-tonratic switch.

11. The combination with a connecting circuit, of means for applying ringing current thereto, means for disconnecting said ringing current, operators telephone apparatus and a listening switch controlling the same, a connection terminal for said connecting circuitl closed while said connecting circuit is extended to a called telephone line, electromagnetic mechanism for reapplying ringing current to said circuit, and means for energizing said mechanism made operable by the coincident closure of said listening switch and said connection terminal. v

12. The combination with a connecting circuit, of a cyclic switch arranged in its various positions to control the circuits associated with said connecting circuit, a source of ringing current adapted to be connected with said circuit in one of the positions of said switch, means for moving said cyclic switch to disconnect Iringing current from fthe circuit, a re-ring key adapted when operated to cause said cyclic switch to move v through the positions of its cycle to reconnect ringing current with the circuit, and means made operative in the actuation of said re-ring key for depriving said cyclic switch of control over certain of the associated circuits as it moves through the positions correspondingwith said circuits.

18. The combination with a connecting circuit, having a connecting terminal, of two sequence switches associated with said circuit, operators telephone apparatus connected with said circuit in the listening-in position of one of said switches, means made operative in closing said connection terminal for moving the other sequence switch out of its normal and into a waiting position, means made operative by said last mentioned switch in moving to its waiiting position for moving said first mentioned switch out of its listening-in position, means made operative by said first mentioned switch in moving out of its listening-in position for moving said last mentioned switch out of its waiting and into a ringingposition, and a source of ringing current connected with said ,connecting circuit in the ringing posi-` tion of said last mentioned switch.

14. The combination with a telephone conv ,necting circuit, of operators telephone apnecting circuit, of operators telephone ap-I i paratus, a telephone switch controlling the connection of the same with said connecting circuit, a called telephone line, a connection switch operated to connect said circuit with'said called line means made operative by the coincident closure of said connection switch and said telephone switch for operating said telephone switch to disconnect the telephone apparatus -from the connecting circuit, a source of ringing current, and means made active in the disconnecting operation of said telephone switch for applying ringing current from said source to said connecting circuit.

16. The combination with a telephone connecting circuit having a connection switch ,for extending the same to a called telephone line, of operators telephone apparatus, a telephone switch controlling the connection of the same with said connecting circuit, a

source of ringing current, a switch controlling the connection of said source with said connecting circuit, and means made operative by the coincident closure of said connection switch and said telephone switch for operating said telephone switch to disconnect the telephone apparatus from the circuit and for operating said ringing switch to connect said source of ringing current with said circuit.

In witness whereof, I hereunto subscribe my name this 3rd day of June, A. D. 1916.

v RALPH [i: QUA'SS. 

